（1）设乙数是x 30-12.5%x=230-12.5%x+12.5%x=2+12.5%x 30-2=2+12.5%x-2 28÷12.5%=12.5%x÷12.5% x=224答：乙数是224．（2） 2 3 ×6+ 2 5 ÷ 8 15 =4+ 3 4 =4 3 4 答：和是4 3 4 ．
